Insulating material is commonly used in the construction industry in a wide variety of forms. Insulating material such as sheathing board is provided in four foot by eight foot sheets and is manufactured from a wide variety of insulating materials.
At times moisture permeable insulating material such an an expanded polystyrene is covered on one side with a foil paper such as a kraft supported aluminum foil to take advantage of the insulating and reflecting properties of metals such as aluminum. The kraft supported aluminum foil outer layer is bonded to the insulating material, such as expanded polystyrene, whereby the kraft side faces the polystyrene. An adhesive is employed to join the two layers.
During the manufacture of kraft supported aluminum foil coated insulating sheets, it is necessary to punch a plurality of holes in the aluminum to permit the material to breathe and let out moisture which would otherwise be trapped in the insulating material. The perforated metal foil on insulating sheet material which is presently used in the building industry has two drawbacks, however, which substantially prevents its achieving its intended purpose. Heretofore the perforations have been punched into the foil prior to the use of adhesive to bond the kraft paper to the expanded polystyrene or other insulating material. in the process of bonding, the adhesive covers the entire polystyrene sheet and tends to render the bond between the foil layer and polystyrene sheet impermeable to moisture. In addition, perforation of the aluminum kraft foil layer causes rips and tears which leave rough particles of the foil which often tend to return to fill in the area where the perforation should be and thus further contribute to sealing the sheathing board against passage of moisture.
Applicant and those in privity with him know of no prior art closer than that discussed above and know of no prior art which anticipates the claims made in this application.